simple signup form. help me debug mycode. new in php

<form method="post" action="reg.php">
    <div id="formStyle">
        <input type="text" name="email" placeholder="Enter your eMail">
        <input type="password" name="pass" placeholder="Enter your desire Password">              
        <input type="text" name="fname" placeholder="Enter your First Name">
        <input type="text" name="mname" placeholder="Enter your Middle Name">
        <input type="text" name="lname" placeholder="Enter your Last name">	
        <button id="logButton" type="submit">Sign Up</button>
                
        <div id="signButton">
             <a class="signLinkStyle" href="login.php">Log In</a>
        </div>             
    </div>			
</form>

<?php
$con = mysqli_connect("localhost","root","123456");
mysqli_select_db("muchies");
if(mysqli_connect_errno())
{
	echo "Failed to connect to mysql:" . mysqli_connect_error();
}

$sql = mysqli_query(
	"INSERT INTO member (userMail,userPass,userFname,userMname,userLname)
	VALUES (NULL,$_POST[email],$_POST[pass],$_POST[fname],$_POST[mname],$_POST[lname])"
);

if(!mysqli_query($con,$add))
{
	die('Error: '.mysqli_error($con));
}
	echo "added";

mysql_close($con);
?>